The present invention relates generally to linkage assemblies, and more particularly, to a linkage for a handle apparatus attached to a tool.
Tools, such as hand tools that may require an actuatable member, such as a piston rod, to be actuated to result in a variety of certain mechanical advantages, are easier to use if smooth movement of the rod is not inhibited. For example, in hand tools such as pressure pumps or vacuum pumps a handle assembly is squeezed together by an operator's hand to actuate a piston rod to move within a cylinder and thereby create either a pressure or a vacuum as is known to those of ordinary skill in the art. For extended use of the piston cylinder assembly and for achieving optimum performance from the hand tool it is advantageous to guide the piston rod of such an assembly in a manner that does not tend to buckle or bind the rod but instead provides for perfectly linear actuation of the rod. Lateral movement of the rod could cause damage to the rod, piston, or cylinder and could also hinder smooth and easy operation of the hand tool. Known linkages attached to the piston rod have been known to suffer from a tendency to buckle or bend the rod during operation of such a hand tool.
The present invention is designed to overcome the above mentioned problems associated with known handle linkages for hand tools and other devices which would benefit from substantial linear movement of a rod without a tendency to buckle or bend the rod. The present invention offers a unique handle linkage for use with such tools as hand held pressure pumps and vacuum pumps as well as other devices of a similar nature.
The present invention includes two handle arms, one secured at its proximal end to the body of a hand tool, such as the cylinder of a pressure pump tool, and a distal end extending therefrom. The second handle arm is movable and rotatably secured to a portion of said first handle arm. The second handle arm proximal end is engaged with a linkage that is secured to a piston rod in one embodiment of the present invention. The distal end of the second handle arm extends therefrom to oppose the distal end of the first handle arm. By forcing the distal end of the second handle arm to move towards the distal end of the first handle arm, the proximal end of the second handle arm is caused to move in a direction either toward or away from the body of the tool depending on whether the tool in this embodiment is a pressure pump (toward) or a vacuum pump (away from). Since the proximal end of the second handle arm is attached by the linkage to the rod of the assembly, as it moves towards the body of the tool in the case of a pressure pump it will drive the rod into the body or cylinder of the tool. The linkage of the present invention is designed to cause the rod to move in a linear fashion and not to bind or buckle as the second handle arm actuates the rod. To accomplish this preferably two linkage members or links are movably engaged with the proximal end of the second handle arm. The two linkage members are rotatably engaged with the rod at their respective ends opposite the ends engaged with the second handle arm. A protruding flange member of each link may be adapted to be engaged within a preferably hourglass shaped slot located in each of two spaced flange ends forming the proximal end of the second handle arm.
The invention will be shown and described in greater detail in the following drawings and detailed description: